Leptin and its receptors have been identified as key regulators of body weight and energy homeostasis. A decrease in tissue sensitivity to leptin leads to the development of obesity and metabolic disorders, such as insulin resistance and dyslipidemia. Mechanisms underlying the development of leptin resistance include mutations in the genes encoding leptin and its receptors, as well as proteins involved in self-regulation of leptin synthesis and blood–brain barrier permeability. Leptin resistance encompasses a complex pathophysiological phenomenon with a number of potential research lines. In this review, we analyze the existing data on the methods used to diagnose leptin resistance.

Despite the existing preventative and therapeutic measures, cardiovascular diseases remain the main cause of temporary disability, long-term disability, and mortality. Obesity is a major risk factor for cardiovascular diseases and their complications. However, not all fat depots have the same inflammatory, paracrine, and metabolic activities. In addition, recent studies have indicated that the accumulation of visceral fat, rather than subcutaneous fat, is associated with increased cardiometabolic risk. However, there is also evidence that increasing the area of visceral fat can help protect against lipotoxicity. This review aims to discuss the contemporary literature regarding the characteristics of the visceral, epicardial, and perivascular fat depots, as well as their associations with cardiovascular disease.

The content of adipokines, pro- and anti-inflammatory cytokines were studied in adipocytes isolated from epicardial and subcutaneous adipose tissue of 24 coronary heart disease patients. The content of leptin and soluble leptin receptor in adipocytes of epicardial adipose tissue was higher by 28.6 and 56.9% and the level of adiponectin was lower by 33% than in adipocytes of the subcutaneous fat. In culture of epicardial adipocytes, the levels of proinflammatory cytokines TNF-α and IL-1 were higher. Subcutaneous adipose tissue adipocytes were characterized by higher levels of anti-inflammatory cytokines IL-10 and FGF-β. In epicardial adipocytes of coronary heart disease patients, the concentrations of leptin, TNF-α, and IL-1 were higher, while the levels of defense regulatory molecules (adiponectin, IL-10, and FGF-β) were lower than in subcutaneous adipocytes.

BackgroundDetermination of the impact of visceral obesity and epicardial adipose tissue thickness on stimulating growth factor levels during hospitalization for myocardial infarction is of potential importance for predicting outcomes and assessing the development of cardiofibrotic changes associated with maladaptive myocardial remodeling. In this study, we aimed to investigate the relationships between epicardial adipose tissue thickness, adipokine profiles, and the stimulating growth factor 2/interleukin-33 signaling system during hospitalization for myocardial infarction, and with the cardiac fibrosis extent 1-year post-MI in patients with visceral obesity.MethodsEighty-eight patients with myocardial infarction were grouped based on their visceral obesity. Serum leptin, adiponectin, stimulating growth factor 2, and interleukin-33 levels were measured on days 1 and 12 and at 1 year. The epicardial adipose tissue widths and the cardiac fibrosis areas were measured on day 12 and at 1 year.ResultsVisceral obesity was associated with epicardial adipose tissue thickness increases, adipokine imbalances, elevated leptin levels, and lower adiponectin levels during early hospitalization, and cardiac fibrosis development. Patients without visceral obesity had higher interleukin-33 and stimulating growth factor 2 levels during early hospitalization and lower cardiac fibrosis rates. Epicardial adipose tissue thickness was positively associated with cardiac fibrosis prevalence and interleukin-33 levels and negatively associated with stimulating growth factor 2 levels. The cardiac fibrosis extent was negatively associated with interleukin-33 levels and positively associated with stimulating growth factor 2 levels.ConclusionsIncreases in epicardial adipose tissue thickness are associated with cardiac fibrosis development 1-year post-myocardial infarction and are higher in patients with visceral obesity. The metabolic activity of the epicardial adipose tissue is associated with elevated interleukin-33 and reduced stimulating growth factor 2 levels.

BackgroundStudying the role of soluble ST2 (sST2) during hospitalization for myocardial infarction (MI) can be helpful for predicting the course of the hospitalization and development of complications.MethodsWe included 88 patients with MI (median age, 58 yr). Depending on the course of the hospitalization, the patients were divided into two groups: the favorable (n=58) and unfavorable (n=30) outcome groups. On days 1 and 12 after MI, serum sST2 and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured by ELISA.ResultsOn day 1, the concentrations of sST2 and NT-proBNP increased 2.4- and 4.5-fold, compared with the controls. Measurements on day 12 showed a significant decrease in the sST2 level (P=0.001), whereas the NT-proBNP level did not change. On day 1, the sST2 level in the unfavorable outcome group was 2-fold higher than that in the favorable outcome group and 3.7-fold higher than in the controls. On day 12, the marker level decreased in both groups. On day 1, the NT-proBNP level in the unfavorable outcome group was 6.8-fold higher than in the controls and 1.8-fold higher than in the favorable outcome group. On day 12, the level of NT-proBNP remained elevated in both groups. Determining the levels of both sST2 and NT-proBNP increases their diagnostic significance (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.7-3.2; areas under curve [AUC] 0.89; P=0.004).ConclusionsThe level of sST2 is a more sensitive indicator during MI hospitalization than NT-proBNP.